Concrete-chute strike-off device

ABSTRACT

A concrete chute strike-off machine or device includes a frame portion adapted to mount to a discharge end of a chute of a concrete delivery truck, a strike-off member adjustably mounted to the frame portion, a sensing device for sensing at least one of a position and orientation of the strike-off member, and a control operable to automatically adjust the strike-off member relative to the frame portion in response to a signal from the sensing device. The device is thus operable to strike-off uncured concrete as the uncured concrete is delivered to a subgrade surface by a chute of a concrete delivery truck. The control is operable to adjust the strike-off member relative to the frame portion while the strike-off member strikes off the uncured concrete at the subgrade surface.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims benefit on U.S. provisional application, Ser. No. 60/539,775, filed Jan. 27, 2004, which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to chutes for concrete delivery trucks and, more particularly, to chutes for concrete delivery trucks that discharge uncured concrete onto a subgrade upon which a concrete slab will be formed.

BACKGROUND OF THE INVENTION

One of the most common practices for the placement of concrete during the construction of slab-on-grade concrete surfaces and floors is to discharge concrete directly from concrete delivery trucks via a chute onto a subgrade upon which the slab will be formed. Discharging the concrete from modem trucks is typically at least partially automated when state-of-the-art trucks are used. In cases where the truck has a front discharge chute, the truck driver is often required to perform the task of controlling the concrete chute from the driver's seat. However, considerable manual labor is required to spread the concrete to a reasonably uniform depth for subsequent strike-off and/or screeding of the placed and spread concrete. Automated machines, such as the Laser Screed™ laser-guided screeding machine manufactured by Somero Enterprises of Houghton, Mich., USA, reduce the manual labor of screeding concrete substantially over large areas. However, in many instances where a screeding machine cannot be used or where the screeding machine is not readily suited for the particular application, the concrete often is spread out or struck-off in a somewhat uniform fashion by manual effort, which is often very labor intensive and costly.

SUMMARY OF THE INVENTION

The present invention provides a chute and laser-guided strike-off and/or screeding device or machine that is operable to strike-off and at least partially finish the uncured concrete placed at a site as it is discharged from the concrete truck delivery chute. In an effort to reduce the labor and cost associated with manual spreading out and striking off of the uncured placed concrete, the device of the present invention, which may be described as a “concrete-chute striking-off and/or screeding machine or device”, may be implemented. The device may be used to strike-off and more evenly finish the concrete substantially immediately as the uncured concrete is directly discharged from the ready-mix concrete truck delivery chute. The expected benefits of the concrete-chute striking off and/or screeding machine of the present invention include that little or no additional manual labor or equipment may be required in order to place, strike-off, rake, or otherwise spread out and screed the uncured concrete to a desired grade elevation at the job site. The present invention thus may be especially useful where current methods and machines are not practical or are unable to be used for a variety of reasons.

According to an aspect of the present invention, a concrete chute strike-off device includes a frame portion adapted to mount to a discharge end of a chute of a concrete delivery truck, a strike-off member adjustably mounted to the frame portion, a sensing device for sensing an elevation, position and/or orientation of the strike-off member, and a control operable to automatically adjust the strike-off member relative to the frame portion in response to a signal from the sensing device. The strike-off device is thus operable to strike-off uncured concrete as the uncured concrete is delivered to a subgrade surface by a chute of a concrete delivery truck. The control is operable to adjust the strike-off member relative to the frame portion while the strike-off member strikes off the uncured concrete at the subgrade surface.

The strike-off member may be pivotally mounted to the frame portion, and the sensing device may comprise a level sensing device. The strike-off member may be pivotable or tiltable about first and second generally orthogonal and generally horizontal pivot axes. The level sensing device may determine a degree of tilt of the strike-off member about the first and second pivot axes. The control may adjust the orientation or tilt of the strike-off member about the first and second pivot axes in response to a signal from the level sensing device.

The strike-off member may be vertically adjustable relative to the frame portion, and the sensing device may comprise a laser receiver for receiving or sensing a laser reference plane of a laser system. The control may vertically adjust the strike-off member relative to the frame portion in response to a signal from the laser receiver.

According to another aspect of the present invention, a method for striking off uncured concrete as it is discharged onto a targeted subgrade surface by a chute of a concrete delivery truck includes providing a concrete strike-off device having a frame portion and a strike-off member adjustably mounted to the frame portion. The frame portion is attached to an end of a chute of a concrete delivery truck. The concrete delivery truck discharges uncured concrete to the subgrade via the chute. The chute provides a channel or conduit for uncured concrete to flow from the concrete delivery truck to the targeted subgrade. The uncured concrete is struck-off as it is discharged to the targeted subgrade by the chute. The strike-off member is adjusted to a desired grade while striking off the uncured concrete.

Therefore, the present invention provides a strike-off device or machine for striking off uncured concrete as it is discharged from a chute of a concrete delivery truck. The strike-off device is operable to strike-off the uncured concrete at a desired grade to limit or reduce the manual labor that otherwise may be required to set or establish the desired grade of the concrete slab as the uncured concrete is discharged onto the targeted subgrade or surface. The strike-off device may be vertically adjusted in response to a laser leveling system to provide the desired grade of the concrete slab. The strike-off device may also or otherwise be tilted forward/rearward about a laterally extending axis and/or side-to-side about a longitudinally extending axis, in order to adjust the orientation or tilt of the strike-off member or device while the strike-off device is striking off the uncured concrete. The present invention thus provides an automatically adjustable strike-off device for striking off and spreading out uncured concrete as it is discharged onto the targeted area or surface by a discharge chute of a concrete delivery truck.

These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a concrete chute striking off device in accordance with the present invention;

FIG. 2 is a hydraulic schematic of a hydraulic system useful with the concrete chute striking off device of the present invention;

FIG. 3 is a block diagram of a control system suitable for use with the concrete chute striking off device of the present invention;

FIG. 4 is a perspective view of the concrete chute striking off device of FIG. 1, shown attached to a concrete delivery truck;

FIG. 5 is a perspective view of another concrete chute striking off device in accordance with the present invention; and

FIG. 6 is a perspective view of another concrete chute striking off device in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depicted therein, a concrete chute screeding or strike-off device or apparatus or machine 10 is operable to strike-off and/or screed freshly placed and uncured concrete at an end of a discharge chute 12 (FIGS. 1 and 4). The apparatus 10 consists of a strike-off plow or member 14 (such as a “V-shaped” strike-off plow or member) attached to a discharge end 16 of the concrete ready-mix truck delivery chute 12. The elevation or height of the V-shaped plow 14 at or above a subgrade is controlled by a control or controller or control system 18 (FIG. 3). The plow 14 thus may be adjusted to and/or maintained at a desired height and may strike off concrete that is discharged from a concrete delivery truck 20 (FIG. 4) at the plow 14 via the delivery chute 12, in order to at least partially or roughly establish the desired grade of the concrete, as discussed below. Optionally, the tilt or angle of the plow may also or otherwise be controlled or adjusted, as also discussed below.

The control means or system 18 may control the elevation of the V-shaped plow, such as in response to a laser control system or the like. For example, such a laser control system may utilize essentially similar laser-based machine control technology as that described by commonly assigned U.S. Pat. No. 4,655,633, which issued Apr. 7, 1987, and which is hereby incorporated herein by reference. Such machine control technology is included within laser-guided screeding machines currently manufactured by Somero Enterprises. Such screeding machines typically are implemented to control the elevation of a screed head that is supported by a telescopic boom assembly. The telescopic boom of such machines may be retracted toward the stationary base of the machine while the screed head may be engaged with uncured concrete that has been previously placed over a subgrade.

The concrete chute strike-off device of the present invention is constructed and operates as discussed below. The V-shaped plow 14 on the concrete chute strike-off device 10 is attached to the lower end of a generally vertical mast member 22 that can slide or move vertically inside a mast support tube 24. The support tube 24 is mounted to a frame 32 and extends generally vertically upwardly therefrom. An actuator 26, such as an electric linear actuator or a hydraulic cylinder (as shown in FIG. 1) or other actuating device, adjusts or controls the relative position of the vertical mast member relative to the mast support tube.

In the illustrated embodiment, a laser receiver 28 is attached to the upper end of the mast member 22. The laser receiver 28 senses the position of a laser plane generated by an on-site laser transmitter (not shown) located at or near or adjacent to the area of operation of the device. The laser receiver generates an electrical output signal, which is directed to the input of a controller or control box 18 located on the screeding apparatus. The controller or control box 18 is operable to adjust the position or extension/retraction of the vertical mast 22 and thus the plow 14 relative to the support tube 24 and the frame 32 in response to the signal from the laser receiver. For example, the controller may operate a hydraulic valve or solenoid valve 27 (FIG. 2), which then controls the position or extension/retraction of the hydraulic cylinder or actuator 26 attached to the vertical mast member 22 and mast support tube 24 (optionally, and alternately, the controller may directly control the position of an electric linear actuator or other actuating device used in place of the hydraulic cylinder, without affecting the scope of the present invention).

During operation, the controller correctively controls or adjusts the elevation position of the vertical mast member, laser receiver, and V-shaped plow relative to the subgrade surface, such that the laser plane generated by the laser transmitter of the laser system remains substantially centered within the “on-grade” portion of the laser receiver's sensing element. Thus, the controller maintains the V-shaped plow at a substantially fixed or constant relative height or distance from the generated laser plane at the site. For example, if the plow, and hence the laser receiver, were to fall below or rise above the desired grade, the controller would receive either a corresponding “low” or “high” signal from the laser receiver. The controller would then output a signal to move or adjust the hydraulic cylinder or electric actuator to accordingly raise or lower the receiver. Therefore, the height or elevation of the V-shaped plow is substantially accurately maintained at the desired “on-grade” elevation position while it engages the uncured concrete during its operation. As used herein, the term “grade” is meant to describe the desired level or height of the concrete on the subgrade or support surface after the concrete has been placed and struck off.

Optionally, and in addition to the elevation control described above, the cutting edge of the V-shaped plow may be controlled so that it remains in a generally horizontal plane during its operation. This may be accomplished by means of pivotal mounting of the plow mast support tube 24 to the frame portion via a dual axis trunnion or central frame portion 30 that is pivotally mounted to an outermost trunnion frame portion 31 of frame 32, which may be mounted to or attached to or at the discharge end of the chute 12. The plow 14, support tube 24 and central frame portion 30 thus may be pivoted about a pair of generally orthogonal pivot axes 34 a, 34 b with respect to the outer frame portion 31. Two pivot axes 34 a, 34 b are thus provided, with each pivot axis being generally perpendicular with respect to the other and oriented in a generally horizontal plane. The first and outer most trunnion axis 34 a may be referred to as a “fore aft trunnion axis”, while the second and innermost trunnion axis 34 b may be referred to as a “side-tilt trunnion axis”. Two independent linear actuators or hydraulic cylinders 36, 38 may control the relative vertical position or rotation of the central assembly (comprising the central frame portion 30, vertical mast members 22, 24, laser receiver 28, and V-shaped plow 14) about both trunnion axes 34 a, 34 b, respectively, and relative to the outer frame portion 31 of frame 32.

In the illustrated embodiment, the controller or control box 18 receives an output signal from a level sensor 40 fixedly-mounted to the mast support tube 24. The level sensor in a particular embodiment of the present invention is of a dual-axis swinging pendulum type, but may comprise other types of level sensors, without affecting the scope of the present invention. Damping fluids or oils of various viscosities may be included within the level sensor to reduce or damp-out the effects of vibrations or jarring movements within the apparatus in an effort to improve the control response characteristics of the device. Other methods of level sensing technology or multiple sensors may optionally be used to measure the degree of levelness of the mast support tube, without affecting the scope of the present invention.

Low friction pivot bearings for the trunnion pivot axes and the fixed ends of the actuators may be housed within the trunnion frame. The trunnion frame subassembly 32 may in turn be fixed to a mounting bracket 42 adapted to be rigidly or otherwise securely attached at the discharge end 16 of the outermost end section of a series of concrete delivery truck chute sections 12 a. Since the entire apparatus is attached at the discharge end 16 of the concrete chute 12, it will move up and down or change angular position relative to the ground based on any movement of the concrete truck 20 and chute 12. However, the response characteristics of the control system are preferably selected such that the hydraulic cylinders or actuators will strive to keep the bottom edge of the V-shaped plow at the desired correct elevation (such as in response to the laser receiver 28) for working the concrete. In addition, the V-shaped plow may be maintained in a generally horizontal plane (such as in response to the level sensors or controls 40) regardless of how the truck or chutes are moved over the support surface.

A general hydraulic schematic suitable for use with the chute strike-off device 10 is shown in FIG. 2, where hydraulic power is made available from a hydraulic pump 44 and motor 46, such as a six horsepower unit (prime mover) or the like, mounted to the concrete truck. Alternately, the concrete truck may directly supply hydraulic and electrical power from its onboard systems through hydraulic and electrical quick-disconnect fittings and connectors or the like, without affecting the scope of the present invention. The screed elevation hydraulic control valve 27, the fore-aft tilt hydraulic control valve 48, and the side-tilt hydraulic control valve 50 are controlled by signals generated by the controller. The laser receiver and level sensors provide input signals to the controller. In effect, the control controls the screed elevation control valve 27 and screed elevation cylinder 26 (or electric actuator) to adjust the elevation of the V-shaped plow in response to a signal from the laser receiver 28, while the control controls the fore-aft control valve 48 and cylinder or actuator 36 and the side-tilt control valve 50 and cylinder or actuator 38 to adjust the orientation of the V-shaped plow in response to the respective level sensors 40.

Apparatus Operation:

Referring now to FIG. 4, an anticipated mode of operation is for the concrete ready-mix truck driver-operator to swing the delivery chute sections 12 a from side to side using the known or standard on-board control functions of the truck. Preferably, and as shown in FIG. 4, the chute 12 is a front discharge chute and is attached to and extends from a forward or front portion of the truck 20 so that the driver/operator may readily view and control the chute from within the cab of the truck. However, the chute may be a rear discharge chute or other type of chute without affecting the scope of the present invention. The chute or chute sections provide a conduit (such as a channel or trough or tube or the like) for the uncured concrete to flow through and/or along from the truck to the subgrade surface at the discharge end of the chute.

While discharging concrete down the chute or chute sections onto the subgrade, the discharging concrete will fall within the receiving area 14 a or “V” of the bi-directional or V-shaped plow 14 and be struck-off to the desired grade by the lateral motion or side-to-side or arcuate motion of the bottom edge of the V-shaped plow. As the concrete is discharged at the plow, the chute (and strike-off device and plow) is pivoted or moved or swung in a side-to-side arcuate motion to place or distribute the concrete over the subgrade while the plow strikes-off the placed or distributed concrete. The elevation and tilt of the V-shaped plow is adjusted and substantially maintained in two axes throughout the lateral swing movement, thus substantially striking off and leveling the uncured concrete engaged by the V-shaped plow. Upon completion of a swing in one direction, the operator may reverse the truck, backing up slightly, and may proceed to repeat the swing and concrete screeding or leveling operation in the opposite direction. This process may be repeated until the entire load of uncured concrete has been discharged and placed at the targeted area. Since the control system is able to keep the bottom edge of the plow on-grade and within a generally horizontal plane, the uncured concrete will be accordingly struck off and substantially leveled. The generated laser plane at the site is directly correlated to the desired “on-grade” finished concrete elevation at the site.

Optionally, an alternate method of operation could allow the driver/operator of the concrete delivery truck and/or controls to continually but very slowly back-up the truck while continuously swinging the chute sections and screeding apparatus from side to side while discharging concrete onto the subgrade. Other methods of placing and striking off the concrete with the chutes and chute strike-off device may be implemented without affecting the scope of the present invention.

After the concrete truck and strike-off device or apparatus have discharged and struck off and substantially leveled the load of concrete, the concrete-chute strike-off apparatus may be set down on the ground, such as off to one side of the poured concrete. The strike-off device or unit may then be detached from the truck at the outermost end of the concrete chute. Alternately, the outer most concrete chute section or sections may remain attached to the strike-off device, without affecting the scope of the present invention. Any hydraulic lines and electrical control cables may then be disconnected, such as by use of quick-disconnect attachments or the like between the truck and the strike-off device. The concrete truck may then be driven away to secure another load of concrete as may be needed and/or a second truck may arrive on site with a full load as needed. The second truck may be equipped the same as the first and preferably may have the same quick disconnect hydraulic and electrical control cables as the first. The concrete chute strike-off device or apparatus may thus be attached to the chute of the second truck and moved into position, and the placing and striking-off process may be continued. Multiple trucks may be equipped in this way to continue strike-off and/or screeding operations indefinitely or at different sites as desired.

Optionally, when the concrete striking off and leveling operations are fully completed for the day, the concrete-chute screeding apparatus may be pressure washed, detached from the last truck, partially disassembled, and stored on-board the truck for transport away from the site. The entire apparatus is preferably light enough in weight such that when partially disassembled for transport, the components can be lifted, carried, and stored away by one or two workers until needed again.

Optionally, and additionally, and with reference to FIG. 5, a vibrating member 52 may be added adjacent to and trailing the direction of movement of the V-shaped plow 14 at a strike-off device 10′. The vibrating member 52 may be vibratable to compact and smooth and screed the placed and struck off and leveled concrete as the chutes and strike-off device are moved over the subgrade surface. The vibrating member 52 may comprise any type of vibratable device or member, such as the types described in U.S. Pat. Nos. 4,655,633; 4,930,935; 6,129,481; 6,152,647; 6,183,160; 6,588,976; 6,623,208 and 6,227,761, and/or U.S. patent applications, Ser. No. 10/266,305, filed Oct. 8, 2002 (Attorney Docket SOM01 P-318C); Ser. No. 10/728,620, filed Dec. 5, 2003 (Attorney Docket SOM01 P-318D); and Ser. No. 10/902,528, filed Jul. 29, 2004 (Attorney Docket SOM01 P-326), which are all hereby incorporated herein by reference. The vibrating member may be generally V-shaped or straight or any other desired or suitable shape to provide the desired finishing characteristics at the rear of the V-shaped or curved plow, without affecting the scope of the present invention. The use of a vibratable or vibrating member may allow the device to finish the concrete surface to an increased degree of surface quality. The vibrating member may be attached to a rear surface of the strike-off member or plow or may be attached to the adjustable frame portion 30 and may be adjustable relative to the frame portion and chutes and subgrade surface with the plow or strike-off member. The strike-off device 10′ may otherwise be substantially similar to the strike-off device 10 discussed above, such that a detailed discussion of the strike-off devices will not be repeated herein. The similar components are referenced in FIG. 4 with the same reference numbers used in connection with the strike-off device 10.

Although shown and described as a generally V-shaped plow, the plow of the strike-off and/or screeding device may be replaced by a curved plow or a crescent-shaped plow or a circular or ring-shaped plow or any other shaped plow or strike-off beam or other suitable strike-off member or the like, without affecting the scope of the present invention. The plow or strike-off member thus may be formed to define the receiving portion or area for receiving the uncured concrete at the subgrade surface and generally in front of the plow or strike-off member such that movement of the plow or strike-off member over and along the concrete at the subgrade surface strikes off the placed uncured concrete and generally established the desired grade of the uncured concrete. Likewise, the vibrating member (if applicable) may comprise any suitable shape, such as a shape that generally corresponds to the shape of the plow or strike-off member, or any other shape as desired, and optionally may comprise two vibrating members oriented at an angle relative to one another.

Optionally, the strike-off member or plow and/or vibrating device (if applicable) may comprise other shapes as desired, depending on the particular application of the strike-off device or apparatus. For example, and with reference to FIG. 6, a concrete chute screeding or strike-off device or apparatus or machine 110 is operable to strike-off and/or screed freshly placed and uncured concrete at a discharge end 116 of a discharge chute 112. The apparatus 110 consists of a strike-off plow or member 114 pivotally attached to a frame portion 132, which is attached to a bracket 142 at the discharge end 116 of the concrete ready-mix truck delivery chute 112. The elevation or height of the strike-off member 114 at or above a subgrade is controlled by a control or controller or control system, such as in a similar manner as described above. The strike-off member 114 is attached to the lower end of the generally vertical mast member 122 (which may slide or move vertically inside a mast support tube 124 via an actuator 126, which may vertically adjust the mast member in response to a signal from a laser receiver 128, as described above).

As shown in FIG. 6, support tube 124 may be mounted to the bracket 142 via a single axis trunnion frame 132, such that the tube 124 (and thus the strike-off member 114) is pivotable about a pivot axis 134 a. The controller or control system may receive an output signal from a level sensor 140 fixedly-mounted to the mast support tube 124, and may adjust the support tube 124 about the pivot axis 134 a in response to the output signal and via an actuator 136, such as in a similar manner as described above.

The lower end of the support tube 124 is attached to an elongated mounting bar or member 135, which is oriented generally normally or orthogonal to the pivot axis 134 a. The strike-off member 114 may comprise a single “non-V-shaped” member or a substantially straight member or beam or the like that is adjustably or movably mounted to the elongated mounting member 135. In the illustrated embodiment, the strike-off member 114 is supported at a forward end 114 a by a generally vertical pivot pin 137 extending generally downwardly from a forward end 135 a of mounting member 135, such that the strike-off member 114 may pivot or swing side to side about the generally vertical pivot pin 137. A rearward end 114 b of the strike-off member 114 may be attached to or supported by a pivot limiting device or “slide-bar” 139 or the like. The slide bar 139 (which may comprise a generally rigid bar or member that extends generally laterally and generally normal or orthogonal to the longitudinal axis of the strike-off member) is slidably or adjustably or movably connected to or engaged with a rearward end 135 b of the elongated mounting member 135, such as slidably received within a receiving portion 135 c at rearward end 135 b of mounting member 135.

The slide bar 139 allows the strike-off member or plow to swing horizontally to either side of the support or mounting member 135, and limits pivotal movement of the strike-off member at the outer ends of the desired pivotal range of motion of the strike-off member. For example, the slide bar 139 may include end plates 139 a that contact the receiving portion 135 c to limit further pivotal movement of the strike-off member in that direction. The strike-off member 114 thus may pivot in one direction as the strike-off apparatus 110 is moved in one direction over the placed concrete, and then may pivot in the other direction toward the other side when the strike-off apparatus is moved in the other direction over the placed concrete. Such a mounting arrangement and pivot limiting means of the strike-off member allows the strike-off member to “get behind” or follow the concrete being placed by the chute 112 when the strike-off apparatus is moving in a left or right generally lateral (or arcuate) direction. The generally straight strike-off member or plow is then able to strike-off the concrete in either the left or right directions. The range of pivotal movement of the strike-off member or plow may be set (and may be dictated by the length of the slide bar) to provide the desired angle of the plow relative to the direction of travel of the strike-off device.

A further advantage of the substantially straight strike-off member and mounting arrangement is that the control system for the strike-off apparatus 110 may be simplified because only one axis of rotation is needed due to the “single edged” strike-off member or plow. Optionally, the strike-off apparatus 110 may also or otherwise include a vibratable member or beam (not shown in FIG. 6) attached or mounted to the mounting member 135.

Optionally, the strike-off and/or screeding apparatus of the present invention may be at least partially supported at the concrete surface, and therefore further controllably stabilized relative to the desired grade. For example, the screeding apparatus may be at least partially supported by a trailing contact face of a plow or the face of a vibrating member that is at least partially supported by the uncured concrete surface, without affecting the scope of the present invention. For example, the strike-off and/or screeding device or apparatus may utilize aspects of the screeding devices described in U.S. patent applications, Ser. No. 10/266,305, filed Oct. 8, 2002 (Attorney Docket SOM01 P-318C); Ser. No. 10/728,620, filed Dec. 5, 2003 (Attorney Docket SOM01 P-318D); and Ser. No. 10/902,528, filed Jul. 29, 2004 (Attorney Docket SOM01 P-326), which are hereby incorporated herein by reference.

Therefore, the present invention provides a concrete strike-off and/or screeding device that is attached at the end of a delivery chute of a concrete delivery truck and that is operable to strike-off and/or level and/or screed the uncured concrete placed on the subgrade by the chute of the truck. The chute strike-off and/or screeding device of the present invention thus may strike-off and/or level the uncured concrete as it is placed at the targeted area, such that manual labor is not required to initially strike-off excess concrete to the desired grade. The device may include a vibrating member or screeding element to further process or work or finish the struck-off concrete at the subgrade.

Changes and modifications to the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law. 

1. A concrete chute strike-off device operable to strike-off uncured concrete as the uncured concrete is delivered to a subgrade surface by a chute of a concrete delivery truck, said concrete chute strike-off device comprising: a frame portion adapted to mount to a discharge end of a chute of a concrete delivery truck; a strike-off member adjustably mounted to said frame portion; a sensing device for sensing at least one of an elevation, position and orientation of said strike-off member; and a control operable to automatically adjust said strike-off member relative to said frame portion in response to a signal from said sensing device, said control being operable to adjust said strike-off member relative to said frame portion while said strike-off member strikes off the uncured concrete at the subgrade surface.
 2. The concrete chute strike-off device of claim 1, wherein said strike-off member is adjustable about a pair of generally orthogonal pivot axes relative to said frame.
 3. The concrete chute strike-off device of claim 2, wherein said sensing device comprises a level sensing device adapted to determine a degree of tilt of said strike-off member about said pair of generally orthogonal pivot axes.
 4. The concrete chute strike-off device of claim 3, wherein said control is operable to adjust the orientation or tilt of said strike-off member about said pair of pivot axes in response to a signal from said level sensing device.
 5. The concrete chute strike-off device of claim 2, wherein said pair of generally orthogonal pivot axes are within a generally horizontal plane.
 6. The concrete chute strike-off device of claim 5, wherein a first pivot axis of said pair of pivot axes comprises a longitudinal axis such that said strike-off member is pivotable side-to-side about said first axis, and wherein a second pivot axis of said pair of pivot axes comprises a lateral axis such that said strike-off member is pivotable forward and backward about said second axis.
 7. The concrete chute strike-off device of claim 6, wherein said strike-off member is pivotable about said first and second axes via respective first and second actuators.
 8. The concrete chute strike-off device of claim 2, wherein said strike-off member is vertically adjustable relative to said frame.
 9. The concrete chute strike-off device of claim 1, wherein said strike-off member is vertically adjustable relative to said frame.
 10. The concrete chute strike-off device of claim 9, wherein said sensing device comprises a laser receiver positioned on a support member extending upward from said strike-off member, said laser receiver sensing a laser reference plane generated by a laser transmitter, said control being operable to vertically adjust said strike-off member in response to a signal from said laser receiver.
 11. The concrete chute strike-off device of claim 1, wherein said strike-off member is formed to define a receiving area in front of said strike-off member, the uncured concrete being placed at said receiving area such that movement of said strike-off member over the subgrade surface strikes off the placed uncured concrete in said receiving area.
 12. The concrete chute strike-off device of claim 11, wherein said strike-off member comprises one of a V-shaped member, a U-shaped member and an arcuately curved member.
 13. The concrete chute strike-off device of claim 1, wherein said strike-off member is pivotally mounted to said frame portion and pivotable about a generally vertical pivot axis.
 14. The concrete chute strike-off device of claim 13, wherein said strike-off member is pivotable about said generally vertical pivot axis within a specified range of pivotal movement, said pivotable movement being limited by a pivot limiting device.
 15. The concrete chute strike-off device of claim 1 including a vibratable member positioned at said strike-off member and operable to vibrate and smooth and compact the concrete surface that is struck off by said strike-off member.
 16. A method for striking off uncured concrete as it is discharged onto a targeted subgrade surface by a chute of a concrete delivery truck, said method comprising: providing a concrete strike-off device having a frame portion and a strike-off member adjustably mounted to said frame portion; attaching said frame portion to an end of a chute of a concrete delivery truck, said chute providing a channel for uncured concrete to flow from said concrete delivery truck to the targeted surface; discharging uncured concrete onto the subgrade surface via said chute; striking off the uncured concrete with said strike-off member as the uncured concrete is discharged to the targeted subgrade surface by said chute; and adjusting said strike-off member to a desired grade while striking off the uncured concrete.
 17. The method of claim 16, wherein adjusting said strike-off member comprises vertically adjusting said strike-off member relative to said frame.
 18. The method of claim 17, wherein vertically adjusting said strike-off member comprises vertically adjusting said strike-off member in response to a signal from a laser receiver positioned on a support member extending upward from said strike-off member.
 19. The method of claim 16, wherein adjusting said strike-off member comprises pivoting said strike-off member about first and second pivot axes relative to said frame portion, said first and second pivot axes being generally orthogonal relative to one another.
 20. The method of claim 19, wherein pivoting or tilting said strike-off member comprises pivoting or tilting said strike-off member in response to a signal from a level sensing device, said level sensing device being adapted to determine a degree of tilt of said strike-off member about said first and second pivot axes.
 21. The method of claim 20, wherein said first pivot axis comprises a longitudinal axis such that said strike-off member is pivotable side-to-side about said first pivot axis, said second pivot axis comprising a lateral axis such that said strike-off member is pivotable forward and backward about said second pivot axis.
 22. The method of claim 16, wherein said strike-off member is formed to define a receiving area in front of said strike-off member, wherein discharging uncured concrete comprises discharging uncured concrete at said receiving area, and wherein striking off the uncured concrete comprises striking off the uncured concrete via movement of said strike-off member over the subgrade surface.
 23. The method of claim 16, wherein adjusting said strike-off member comprises pivoting said strike-off member relative to said frame portion about a generally vertical pivot axis.
 24. The method of claim 23, wherein pivoting said strike-off member comprises pivoting said strike-off member within a specified range of pivotal movement and limiting pivotal movement of said strike-off member.
 25. The method of claim 16, wherein providing a concrete strike-off device comprises providing a concrete strike-off device having a vibratable member positioned at said strike-off member, said method including vibrating said vibratable member to vibrate and smooth and compact the concrete surface that is struck off by said strike-off member.
 26. A concrete chute strike-off device operable to strike-off uncured concrete as the uncured concrete is delivered by a chute of a concrete delivery truck, said concrete chute strike-off device comprising: a frame portion adapted to mount to a discharge end of a chute of a concrete delivery truck; a strike-off member adjustably mounted to said frame portion, said strike-off member being vertically adjustable relative to said frame portion, said strike-off member being pivotally adjustable about at least one generally horizontal pivot axis; at least one sensing device for sensing a degree of tilt of said strike-off member about said at least one pivot axis; and a control operable to automatically adjust said strike-off member relative to said frame portion about said at least one pivot axis in response to at least one signal from said at least one sensing device, said control being operable to adjust said strike-off member relative to said frame portion while said strike-off member strikes off the uncured concrete at the subgrade surface.
 27. The concrete chute strike-off device of claim 26, wherein said at least one pivot axis comprises first and second pivot axes and said at least one sensing device comprises first and second sensing devices.
 28. The concrete chute strike-off device of claim 27, wherein said first and second pivot axes are generally orthogonal relative to one another.
 29. The concrete chute strike-off device of claim 28, wherein said first pivot axis comprises a longitudinal axis such that said strike-off member is pivotable side-to-side about said first pivot axis, and wherein said second pivot axis comprises a lateral axis such that said strike-off member is pivotable forward and backward about said second pivot axis.
 30. The concrete chute strike-off device of claim 26 including a laser receiver positioned on a support member extending upward from said strike-off member, said laser receiver sensing a laser reference plane generated by a laser system, said control being operable to vertically adjust said strike-off member in response to a signal from said laser receiver.
 31. The concrete chute strike-off device of claim 26, wherein said strike-off member is formed to define a receiving area in front of said strike-off member, the uncured concrete being placed at said receiving area such that movement of said strike-off member relative to the subgrade surface strikes off the placed uncured concrete in said receiving area.
 32. The concrete chute strike-off device of claim 31, wherein said strike-off member comprises one of a V-shaped member, a U-shaped member and an arcuately curved member.
 33. The concrete chute strike-off device of claim 26, wherein said strike-off member is pivotally mounted to said frame portion and pivotable about a generally vertical pivot axis relative to said frame portion.
 34. The concrete chute strike-off device of claim 33, wherein said strike-off member comprises a substantially straight member.
 35. The concrete chute strike-off device of claim 26 including a vibratable member positioned at said strike-off member and operable to vibrate and smooth and compact the concrete surface that is struck off by said strike-off member.
 36. A concrete delivery and spreading assembly, said concrete delivery and spreading assembly being attachable to a concrete delivery truck, said concrete delivery and spreading assembly comprising: a chute section configured to attach to a discharge of the concrete delivery truck, said chute section comprising a conduit along which uncured concrete flows as the concrete is discharged from the delivery truck; a concrete strike-off device attached at an end of said chute section for striking off uncured concrete discharged from said chute section, said concrete strike-off device comprising: a frame portion attached to said end of said chute section; and a strike-off member adjustably mounted to said frame portion; and a control operable to automatically adjust said strike-off member relative to said frame portion to strike-off the placed concrete at a desired grade, said control being operable to adjust said strike-off member relative to said frame portion while said strike-off member strikes off the uncured concrete at the subgrade surface.
 37. The concrete delivery and spreading assembly of claim 36, wherein said control is operable to vertically adjust said strike-off member relative to said frame portion in response to an elevation sensing device.
 38. The concrete delivery and spreading assembly of claim 36, wherein said strike-off member is pivotally adjustable about first and second pivot axes relative to said frame portion, said first and second axes being generally orthogonal.
 39. The concrete delivery and spreading assembly of claim 38 including a level sensing device adapted to determine a degree of tilt of said strike-off member about said first and second pivot axes, said control being operable to adjust the orientation of said strike-off member about said first and second pivot axes in response to a signal from said level sensing device.
 40. The concrete delivery and spreading assembly of claim 36, wherein said strike-off member is formed to define a receiving area in front of said strike-off member, the uncured concrete being placed at said receiving area such that movement of said strike-off member relative to the subgrade surface strikes off the placed uncured concrete in said receiving area.
 41. The concrete delivery and spreading assembly of claim 36, wherein said strike-off member is pivotally mounted to said frame portion and pivotable about a generally vertical pivot axis.
 42. The concrete delivery and spreading assembly of claim 41, wherein said strike-off member is pivotable about said generally vertical pivot axis within a specified range of pivotal movement, said pivotable movement being limited by a pivot limiting device.
 43. The concrete delivery and spreading assembly of claim 42, wherein said strike-off member is pivotally adjustable about a generally horizontal pivot axis relative to said frame portion.
 44. The concrete delivery and spreading assembly of claim 36 including a vibratable member positioned at said strike-off member and operable to vibrate and smooth and compact the concrete surface that is struck off by said strike-off member. 